Home > Publications database > Vergleich verschiedener Energiediskretisierungsmodelle bei der digitalen Berechnung radialer und azimutaler Xenontransienten am Beispiel von HTR-Cores |
Book/Report | FZJ-2016-03453 |
;
1977
Kernforschungsanlage Jülich, Verlag
Jülich
Please use a persistent id in citations: http://hdl.handle.net/2128/11670
Report No.: Juel-1387
Abstract: The investigation concerns the influence of different few-group energy models for the neutron flux in computing xenon-induced spatial power instabilities in thermal reactors by the aid of the multi-group theory. Comparative transient calculations with a 1-, 2-, 4- and 7-group model have been performed at two typical HTR-models using a finite difference program. We considered the first azimuthal and the first radial oscillation mode of the cylindrical cores. The dependence of essential oscillation parameters like damping factor and period on the nurnber of energy groups and on the choice of the energy intervals is determined. Trends are explained and the increased expenditure of camputer work at larger group numbers is discussed in relation to the profit to accuracy recognizable therefrom. Essential results are, that the one-group formalism proves to be totally unsuitable for such calculations and that not unimportant but considerably case-dependent differences are also found to exist between the multigroup calculations. These latter effects are not merely due to differently calculated steady-state power density profiles.
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